HIGH-RESOLUTION CHROMOSOME ANALYSIS AND IN-SITU HYBRIDIZATION ON AMNIOTIC-FLUID FOR DIAGNOSIS OF A CRYPTIC TRANSLOCATION

We report a cryptic translocation ascertained in a family after the bi rth of a mentally retarded proband. High resolution chromosome examina tion revealed that the father had a subtle translocation between chrom osome 5 and chromosome 13, 46, XY, t(5;13) (q35.2;q34). Two specific, non-routine techniques were associated for prenatal diagnosis: high re solution cytogenetic studies on the amniotic fluid and fluorescent in situ hybridization with YACs as specific telomeric probes. The fetus h ad the same cryptic translocation as his father. (C) 1998 John Wiley & Sons, Ltd.